Как мне правильно отправить дейтаграмму?

import java.net.*;
import java.io.*;

class J_ip {
	private static DatagramSocket ds;
	private static String request_search = 
		"M-SEARCH * HTTP/1.1\r\n" +
		"Host: 239.255.255.250:1900\r\n" +
		"Man: \"ssdp:discover\"\r\n" +
		"ST: upnp:rootdevice\r\n" +
		"MX: 3\r\n" +
		"User-Agent: upnp-ip\r\n" +
		"\r\n"
		;

	public static void main ( String args [ ] ) throws SocketException, UnknownHostException {

		byte[] ma = new byte[] { (byte)239, (byte)255, (byte)255, (byte)250 };
		InetAddress ia = InetAddress.getByAddress ( ma );
		ds = new DatagramSocket ( 12345, ia );
		
		byte[] brequest_search = request_search.getBytes ( );
		DatagramPacket p = new DatagramPacket ( brequest_search, brequest_search.length, ia, 1900 ); 
		try { 
			ds.send ( p ); 
		} catch ( IOException exp ) {
			System.out.println ( "не отправлено" );
		}
	}
}